3 files changed, 176 insertions, 0 deletions

diff --git a/arch/blackfin/Kconfig b/arch/blackfin/Kconfig
index 26ebb0e8c431..cc789b988f3a 100644
--- a/arch/blackfin/Kconfig
+++ b/arch/blackfin/Kconfig
@@ -1164,6 +1164,20 @@ config DEBUG_BFIN_NO_KERN_HWTRACE
           Say Y here to disable hardware tracing in some known "jumpy" pieces
           of code so that the trace buffer will extend further back.
 
+config EARLY_PRINTK
+        bool "Early printk" 
+        default n
+        help
+          This option enables special console drivers which allow the kernel
+          to print messages very early in the bootup process.
+
+          This is useful for kernel debugging when your machine crashes very
+          early before the console code is initialized. After enabling this
+          feature, you must add "earlyprintk=serial,uart0,57600" to the
+          command line (bootargs). It is safe to say Y here in all cases, as
+          all of this lives in the init section and is thrown away after the
+          kernel boots completely.
+
 config DUAL_CORE_TEST_MODULE
         tristate "Dual Core Test Module"
         depends on (BF561)
diff --git a/arch/blackfin/kernel/Makefile b/arch/blackfin/kernel/Makefile
index 243883ec6de1..8aeb6066b19b 100644
--- a/arch/blackfin/kernel/Makefile
+++ b/arch/blackfin/kernel/Makefile
@@ -13,3 +13,4 @@ obj-$(CONFIG_MODULES)                += module.o
 obj-$(CONFIG_BFIN_DMA_5XX)           += bfin_dma_5xx.o
 obj-$(CONFIG_DUAL_CORE_TEST_MODULE)  += dualcore_test.o
 obj-$(CONFIG_KGDB)                   += kgdb.o
+obj-$(CONFIG_EARLY_PRINTK)           += early_printk.o
diff --git a/arch/blackfin/kernel/early_printk.c b/arch/blackfin/kernel/early_printk.c
new file mode 100644
index 000000000000..9bf61706694f
--- /dev/null
+++ b/arch/blackfin/kernel/early_printk.c
@@ -0,0 +1,161 @@
+/*
+ * File:         arch/blackfin/kernel/early_printk.c
+ * Based on:     arch/x86_64/kernel/early_printk.c
+ * Author:       Robin Getz <rgetz@blackfin.uclinux.org
+ *
+ * Created:      14Aug2007
+ * Description:  allow a console to be used for early printk
+ *
+ * Modified:
+ *               Copyright 2004-2007 Analog Devices Inc.
+ *
+ * Bugs:         Enter bugs at http://blackfin.uclinux.org/
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/serial_core.h>
+#include <linux/console.h>
+#include <linux/string.h>
+#include <asm/blackfin.h>
+#include <asm/irq_handler.h>
+#include <asm/early_printk.h>
+
+#ifdef CONFIG_SERIAL_BFIN
+extern struct console *bfin_earlyserial_init(unsigned int port,
+                                                unsigned int cflag);
+#endif
+
+static struct console *early_console;
+
+/* Default console
+ * Port n == ttyBFn
+ * cflags == UART output modes
+ */
+#define DEFAULT_PORT 0
+#define DEFAULT_CFLAG CS8|B57600
+
+#ifdef CONFIG_SERIAL_CORE
+/* What should get here is "0,57600" */
+static struct console * __init earlyserial_init(char *buf)
+{
+        int baud, bit;
+        char parity;
+        unsigned int serial_port = DEFAULT_PORT;
+        unsigned int cflag = DEFAULT_CFLAG;
+
+        serial_port = simple_strtoul(buf, &buf, 10);
+        buf++;
+
+        cflag = 0;
+        baud = simple_strtoul(buf, &buf, 10);
+        switch (baud) {
+        case 1200:
+                cflag |= B1200;
+                break;
+        case 2400:
+                cflag |= B2400;
+                break;
+        case 4800:
+                cflag |= B4800;
+                break;
+        case 9600:
+                cflag |= B9600;
+                break;
+        case 19200:
+                cflag |= B19200;
+                break;
+        case 38400:
+                cflag |= B38400;
+                break;
+        case 115200:
+                cflag |= B115200;
+                break;
+        default:
+                cflag |= B57600;
+        }
+
+        parity = buf[0];
+        buf++;
+        switch (parity) {
+        case 'e':
+                cflag |= PARENB;
+                break;
+        case 'o':
+                cflag |= PARODD;
+                break;
+        }
+
+        bit = simple_strtoul(buf, &buf, 10);
+        switch (bit) {
+        case 5:
+                cflag |= CS5;
+                break;
+        case 6:
+                cflag |= CS5;
+                break;
+        case 7:
+                cflag |= CS5;
+                break;
+        default:
+                cflag |= CS8;
+        }
+
+#ifdef CONFIG_SERIAL_BFIN
+        return bfin_earlyserial_init(serial_port, cflag);
+#else
+        return NULL;
+#endif
+
+}
+#endif
+
+int __init setup_early_printk(char *buf)
+{
+
+        /* Crashing in here would be really bad, so check both the var
+           and the pointer before we start using it
+         */
+        if (!buf)
+                return 0;
+
+        if (!*buf)
+                return 0;
+
+        if (early_console != NULL)
+                return 0;
+
+#ifdef CONFIG_SERIAL_BFIN
+        /* Check for Blackfin Serial */
+        if (!strncmp(buf, "serial,uart", 11)) {
+                buf += 11;
+                early_console = earlyserial_init(buf);
+        }
+#endif
+#ifdef CONFIG_FB
+                /* TODO: add framebuffer console support */
+#endif
+
+        if (likely(early_console)) {
+                early_console->flags |= CON_BOOT;
+
+                register_console(early_console);
+                printk(KERN_INFO "early printk enabled on %s%d\n",
+                        early_console->name,
+                        early_console->index);
+        }
+
+        return 0;
+}
+
+early_param("earlyprintk", setup_early_printk);